Firefighters were called to a suspected gas leak on Conduit Street in Mayfair.
Around 200 people were evacuated from an end-of-terrace shop and a corden was put in place.
Station Commander Paul Green, who was at the scene, said: "Crews were initially called to a strong smell of gas in the basement of a building.
"Around 200 people were evacuated from the building and surrounding properties and a 25m corden was put in place as a precaution.
"Firefighters worked with partner agencies, including the gas authority whose engineers carried out an investigation.
"Conduit Street was shut between Savile Row and New Bond Street and we advised motorists to avoid the area where possible as there was significant disruption."
The Brigade was called at 1317 and the incident was over for firefighters by 1904. One fire engine from Soho Fire station attended.